As a data-rich sport, cycling is filled with riders discussing VO2Max, peak power output (PPO), and functional threshold power (FTP). These terms are associated with cycling performance, but how valuable are they and how can a laboratory test provide accurate data to measure these numbers?
WHAT IS A LABORATORY PERFORMANCE TEST?
A performance test provides information regarding the factors associated with cycling performance. The testing is typically conducted under controlled conditions in a laboratory environment. The testing procedure should provide cyclists and coaches with beneficial information.
Tests are valid if they measure what they claim to measure.
For example, performance tests for cyclists should produce data that accurately predicts performance. Reliability refers to the repeatability of the results. In other words, we would expect the same results if we repeated the same testing protocol on the same athlete, using the same equipment under the same conditions.
A laboratory-based test is more reliable than field testing, primarily due to its standardised protocol, equipment (accurate and calibrated) and consistent environmental conditions.
WHY DO WE TEST?
Testing is done to accurately and objectively determine training zones, assess training status and physiological profile, as well as to evaluate performance improvements.
With accurate training zones, we can create a broad range of intensities that can target specific physiological systems and thus improve training effectiveness. A rider can achieve optimal improvements and progress by training at the correct intensity levels, which targets the correct physiological systems. Training load, stress, and fatigue can also be determined with this data.
A cyclist’s training status refers to their current level of ability. In addition to providing cyclists with a clear idea of their current level, physiological profiling gives riders an indication of where they are relative to others at their level of experience, whether amateur, or professional.
In order to determine if the training has been effective, and to ensure the cyclist continues to train at the correct intensity levels, it is essential to re-assess the zones and physiological level of the cyclist at specific times. Typically, testing is done at a similar time every year, such as at the start of each season or the start of the main training cycle.
Determinants of endurance performance
A laboratory-based performance test will typically measure the variables below, due to the association between these variables and cycling performance.
- VO2Max: The maximal oxygen uptake represents the highest amount of oxygen that an individual can consume during exercise. There is a strong association between VO2Max and endurance performance.
- Lactate or functional threshold: The maximal intensity (power output or heart rate) that can be maintained for a prolonged period (~40 to 60 minutes).
- Peak Power Output (PPO): The peak power output is the average power output during the final minute of a VO2Max test. Peak power output is a strong predictor of 40km time trial performance.
Laboratory testing can go one step further, where one can assess a cyclist’s metabolic profile and ability to utilise lactate and fat as fuel sources.
Which test should you do?
The most common types of performance tests done by cyclists include:
- 1. PPO test/ VO2Max test
- 2. Metabolic testing
- 2a. Lactate accumulation assessment
- 2b. Fat max assessment
1. VO2Max or PPO test
These results will identify your individual training zones, which can improve your training by providing an accurate measure of your intensity.
The VO2Max test should provide you with the average power output for the final stage, which is the peak power output. A power meter will give you and your coach a very clear indication of what sort of power output you should aim for during your high-intensity interval training.
As well as determining your threshold power output, the VO2Max test will also determine the equivalent heart rate training zones.
2. Metabolic testing
During a ride, our bodies produce energy from 3 internal fuel sources; fat, carbohydrates, or protein, depending on the workload. The two main sources of energy during exercise are carbohydrates and fats. Exercise intensity is the biggest factor influencing how much energy we derive from each of these sources.
At lower intensities, fat represents the majority of our fuel, with a small proportion of carbohydrates. As exercise intensity increases, our body will begin to utilise less fat and increasing amounts of carbohydrates. This is simply due to how much energy our body needs to produce, as well as the rate at which this energy needs to be produced. If you are riding at a low intensity, less energy production is required, and therefore metabolising fat (which takes longer), is the preferred energy source. Once intensity increases and an increased energy demand is required, we cannot oxidise fat at a rate that matches this demand. Therefore, we shift to using higher amounts of carbohydrates.
We only have a limited amount of internal carbohydrate stores (approximately 600g) and therefore need to spare these sources when racing. Teaching your body to utilise greater amounts of intramuscular triglycerides (IMTG) or fat within the muscle, will result in greater energy production at lower and moderate intensities, and allow a carbohydrate sparing effect.
Likewise, with carbohydrate oxidation, our bodies have a way of using excess pyruvate (an energy intermediate). This is done by converting pyruvate to lactate and then re-distributing this lactate to other tissues to be converted back to pyruvate and then continuing along in the cellular respiration cycle. This is particularly useful at intensities ranging from 75 to 85 and even 90% of threshold or FTP.
Both the ability to oxidise fat and lactate are signs of mitochondrial function, and riders who oxidise high amounts of fat across a range of intensities, as well as have low lactate levels across a range of intensities can be seen as well trained and have an excellent oxidative capacity. A great example is Tour de France riders, who are exceptional in their ability to use both fat and lactate as fuel sources.
For most of us, improving these systems is vital to endurance performance and racing. Riders will have different fat max and lactate accumulation intensities, and determining their metabolic profile is vital to ensuring maximal improvement of these systems.
2a. Lactate Accumulation Assessment (LAA)
The purpose of this assessment is to define training intensities that allow you to target the metabolic pathways used to oxidise carbohydrates.
The ‘Lactate Accumulation Assessment’ test is performed to determine the intensity at which your body is producing more lactate than you can metabolise (use). During low-intensity exercise blood lactate levels will remain at near resting levels as clearance matches production. Lactate levels will always increase as exercise intensity increases, however, lactate is continually utilised through either oxidising within the muscle or shuttling to other muscle groups and organs to use as a fuel source. Therefore, as exercise intensity increases there comes a breakpoint, where the production of blood lactate exceeds the ability to oxidise lactate.
The results of this assessment will allow training at specific intensities where lactate has increased to a level greater than baseline, but can still be maintained for prolonged durations should be targeted to assist the shift of your lactate curve. Such focused training will assist by shifting your lactate accumulation curve to the right through increasing mitochondrial enzymes, mitochondrial biogenesis, lactate transport proteins, lactate dehydrogenase, and other key enzymes and proteins.
2b. Fat Max Testing
The results of this assessment will allow you to plan training sessions to increase fat oxidation by training at or near the intensity which yields a maximal fat oxidation rate. This will over time improve your ability to extract the fat within the muscle as a fuel source. In general, fat oxidation (usage) tends to increase from low to moderate exercise intensity and then decrease as the intensity increases further. There can be large differences in maximal fat oxidation rates between athletes, even athletes of similar abilities.
There is a typical range of 10% which is applied to this value, and performing endurance rides within this range will result in maximal fat oxidation and upregulation of the systems involved with fat oxidation.
book your test
If you’re interested in doing one of these laboratory performance tests to establish your VO2Max, peak power, functional threshold or metabolic physiology, you can make your booking at one of our labs.